Strange behaviour when removing item from state array
I have an array in state which contains various components. When I click the remove button on one of the components, it removes the first item from the array instead. I only seem to have this problem when using components in the array, it works fine with an array of strings.
Parent component:
addItem = (block) => {
const add = [...this.state.items, block];
this.setState({items: add})
}
removeItem = (index) => {
const remove = [...this.state.items];
remove.splice(index, 1);
this.setState({items: remove})
}
render(){
return(
<div className="Board">
<div className="BoardContainer">
{this.state.items.map((item, index) => { return <Item remove= {this.removeItem} key={index} >{item}</Item>})}
</div>
<button onClick={() => this.addItem(<BannerImage />)}>Banner Image</button>
<button onClick={() => this.addItem(<ShortTextCentered />)}>Short Text Centered</button>
</div>
)
}
Child component:
export class Item extends React.Component {
handleRemove = () => {
this.props.remove(this.props.index)
}
render() {
return (
<div className="item">
{this.props.children}
<button onClick={this.handleRemove} >Remove</button>
</div>
)
}
}
javascript arrays reactjs
edited Nov 25 '18 at 21:45
zeduke
8518
asked Nov 25 '18 at 18:09
George BleasdaleGeorge Bleasdale
436
add a comment |
I have an array in state which contains various components. When I click the remove button on one of the components, it removes the first item from the array instead. I only seem to have this problem when using components in the array, it works fine with an array of strings.
Parent component:
addItem = (block) => {
const add = [...this.state.items, block];
this.setState({items: add})
}
removeItem = (index) => {
const remove = [...this.state.items];
remove.splice(index, 1);
this.setState({items: remove})
}
render(){
return(
<div className="Board">
<div className="BoardContainer">
{this.state.items.map((item, index) => { return <Item remove= {this.removeItem} key={index} >{item}</Item>})}
</div>
<button onClick={() => this.addItem(<BannerImage />)}>Banner Image</button>
<button onClick={() => this.addItem(<ShortTextCentered />)}>Short Text Centered</button>
</div>
)
}
Child component:
export class Item extends React.Component {
handleRemove = () => {
this.props.remove(this.props.index)
}
render() {
return (
<div className="item">
{this.props.children}
<button onClick={this.handleRemove} >Remove</button>
</div>
)
}
}
javascript arrays reactjs
edited Nov 25 '18 at 21:45
zeduke
8518
asked Nov 25 '18 at 18:09
George BleasdaleGeorge Bleasdale
436
add a comment |
I have an array in state which contains various components. When I click the remove button on one of the components, it removes the first item from the array instead. I only seem to have this problem when using components in the array, it works fine with an array of strings.
Parent component:
addItem = (block) => {
const add = [...this.state.items, block];
this.setState({items: add})
}
removeItem = (index) => {
const remove = [...this.state.items];
remove.splice(index, 1);
this.setState({items: remove})
}
render(){
return(
<div className="Board">
<div className="BoardContainer">
{this.state.items.map((item, index) => { return <Item remove= {this.removeItem} key={index} >{item}</Item>})}
</div>
<button onClick={() => this.addItem(<BannerImage />)}>Banner Image</button>
<button onClick={() => this.addItem(<ShortTextCentered />)}>Short Text Centered</button>
</div>
)
}
Child component:
export class Item extends React.Component {
handleRemove = () => {
this.props.remove(this.props.index)
}
render() {
return (
<div className="item">
{this.props.children}
<button onClick={this.handleRemove} >Remove</button>
</div>
)
}
}
javascript arrays reactjs
edited Nov 25 '18 at 21:45
zeduke
8518
asked Nov 25 '18 at 18:09
George BleasdaleGeorge Bleasdale
436
I have an array in state which contains various components. When I click the remove button on one of the components, it removes the first item from the array instead. I only seem to have this problem when using components in the array, it works fine with an array of strings.
Parent component:
addItem = (block) => {
const add = [...this.state.items, block];
this.setState({items: add})
}
removeItem = (index) => {
const remove = [...this.state.items];
remove.splice(index, 1);
this.setState({items: remove})
}
render(){
return(
<div className="Board">
<div className="BoardContainer">
{this.state.items.map((item, index) => { return <Item remove= {this.removeItem} key={index} >{item}</Item>})}
</div>
<button onClick={() => this.addItem(<BannerImage />)}>Banner Image</button>
<button onClick={() => this.addItem(<ShortTextCentered />)}>Short Text Centered</button>
</div>
)
}
Child component:
export class Item extends React.Component {
handleRemove = () => {
this.props.remove(this.props.index)
}
render() {
return (
<div className="item">
{this.props.children}
<button onClick={this.handleRemove} >Remove</button>
</div>
)
}
}
javascript arrays reactjs
javascript arrays reactjs
edited Nov 25 '18 at 21:45
zeduke
8518
asked Nov 25 '18 at 18:09
George BleasdaleGeorge Bleasdale
436
edited Nov 25 '18 at 21:45
zeduke
8518
asked Nov 25 '18 at 18:09
George BleasdaleGeorge Bleasdale
436
edited Nov 25 '18 at 21:45
zeduke
8518
edited Nov 25 '18 at 21:45
zeduke
8518
edited Nov 25 '18 at 21:45
zeduke
8518
8518
asked Nov 25 '18 at 18:09
George BleasdaleGeorge Bleasdale
436
asked Nov 25 '18 at 18:09
George BleasdaleGeorge Bleasdale
436
asked Nov 25 '18 at 18:09
George BleasdaleGeorge Bleasdale
436
436
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
You used inside your component 'this.props.index' but you didn't pass the index to your component.
you should do something like this:
{this.state.items.map((item, index) => { return <Item remove={this.removeItem} key={index} index={index} >{item}</Item>})}
answered Nov 25 '18 at 18:18
Tom MendelsonTom Mendelson
55439
add a comment |
Array.prototype.splice() mutates the array, so it's better not to use splice() with React.
Easiest to use Array.prototype.filter() to create a new array.
Furthermore working with unique id's rather than indexes prevents from unexpected results.
let filteredArray = this.state.item.filter(x=> x!== e.target.value)
this.setState({item: filteredArray});
answered Nov 25 '18 at 18:21
Ole EH DufourOle EH Dufour
1,11911122
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
You used inside your component 'this.props.index' but you didn't pass the index to your component.
you should do something like this:
{this.state.items.map((item, index) => { return <Item remove={this.removeItem} key={index} index={index} >{item}</Item>})}
answered Nov 25 '18 at 18:18
Tom MendelsonTom Mendelson
55439
add a comment |
You used inside your component 'this.props.index' but you didn't pass the index to your component.
you should do something like this:
{this.state.items.map((item, index) => { return <Item remove={this.removeItem} key={index} index={index} >{item}</Item>})}
answered Nov 25 '18 at 18:18
Tom MendelsonTom Mendelson
55439
add a comment |
You used inside your component 'this.props.index' but you didn't pass the index to your component.
you should do something like this:
{this.state.items.map((item, index) => { return <Item remove={this.removeItem} key={index} index={index} >{item}</Item>})}
answered Nov 25 '18 at 18:18
Tom MendelsonTom Mendelson
55439
You used inside your component 'this.props.index' but you didn't pass the index to your component.
you should do something like this:
{this.state.items.map((item, index) => { return <Item remove={this.removeItem} key={index} index={index} >{item}</Item>})}
answered Nov 25 '18 at 18:18
Tom MendelsonTom Mendelson
55439
answered Nov 25 '18 at 18:18
Tom MendelsonTom Mendelson
55439
answered Nov 25 '18 at 18:18
Tom MendelsonTom Mendelson
55439
answered Nov 25 '18 at 18:18
Tom MendelsonTom Mendelson
55439
55439
add a comment |
add a comment |
Array.prototype.splice() mutates the array, so it's better not to use splice() with React.
Easiest to use Array.prototype.filter() to create a new array.
Furthermore working with unique id's rather than indexes prevents from unexpected results.
let filteredArray = this.state.item.filter(x=> x!== e.target.value)
this.setState({item: filteredArray});
answered Nov 25 '18 at 18:21
Ole EH DufourOle EH Dufour
1,11911122
add a comment |
Array.prototype.splice() mutates the array, so it's better not to use splice() with React.
Easiest to use Array.prototype.filter() to create a new array.
Furthermore working with unique id's rather than indexes prevents from unexpected results.
let filteredArray = this.state.item.filter(x=> x!== e.target.value)
this.setState({item: filteredArray});
answered Nov 25 '18 at 18:21
Ole EH DufourOle EH Dufour
1,11911122
add a comment |
Array.prototype.splice() mutates the array, so it's better not to use splice() with React.
Easiest to use Array.prototype.filter() to create a new array.
Furthermore working with unique id's rather than indexes prevents from unexpected results.
let filteredArray = this.state.item.filter(x=> x!== e.target.value)
this.setState({item: filteredArray});
answered Nov 25 '18 at 18:21
Ole EH DufourOle EH Dufour
1,11911122
Array.prototype.splice() mutates the array, so it's better not to use splice() with React.
Easiest to use Array.prototype.filter() to create a new array.
Furthermore working with unique id's rather than indexes prevents from unexpected results.
let filteredArray = this.state.item.filter(x=> x!== e.target.value)
this.setState({item: filteredArray});
answered Nov 25 '18 at 18:21
Ole EH DufourOle EH Dufour
1,11911122
edited Nov 25 '18 at 18:26
answered Nov 25 '18 at 18:21
Ole EH DufourOle EH Dufour
1,11911122
answered Nov 25 '18 at 18:21
Ole EH DufourOle EH Dufour
1,11911122
answered Nov 25 '18 at 18:21
Ole EH DufourOle EH Dufour
1,11911122
1,11911122
add a comment |
add a comment |
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